Electrophysiological findings in Bietti's crystalline dystrophy

Purpose: The aim was to investigate multifocal electroretinogram (mfERG) findings in Bietti's crystalline dystrophy (BCD) using a retrospective, non-interventional, consecutive case series. Methods: Five patients, two women and three men (mean age 31.8-years), clinically diagnosed with BCD underwent full-field electroretinogram (ffERG) and mfERG using Burian Allen bipolar contact lens electrode on the VERIS Science 5.2.1X system. The ffERG and mfERG parameters of patients with Bietti's crystalline dystrophy were compared with age-matched normal subjects. The N1, P1 amplitudes and implicit times of the mfERG for the six concentric rings were analysed. Results: The ffERG showed significant decreases in the amplitude of the scotopic and photopic responses in all patients; however, implicit times were only mildly prolonged. Rod response implicit times appeared to be more affected than the cone responses. The N1 and P1 amplitudes of mfERG showed a significant decrease in all rings in all patients. N1 implicit times were significantly delayed in rings 3, 4 and 5. The P1 implicit time was significantly delayed in all rings except 1 and 6. Conclusion: The mfERG in Bietti's crystalline dystrophy can provide insight into the functional retina and objectively help to quantify the extent of retinal damage.